1. Field of the Invention
The present invention relates to an optical disk device to be mounted on electronic equipment such as a personal computer or a notebook computer.
2. Description of the Related Art
For an optical disk device, a CD-ROM, a CD-R/RW and a DVD have already been used practically, and an application to each field and the development of an increase in a performance have been actively carried out. In recent years, particularly, the rate of propagation of an optical disk device built in a personal computer has also been increased with a rapid expansion of a market for the personal computer.
FIG. 9 is a perspective view showing a conventional optical disk device.
In FIG. 9, 1 denotes an optical disk device. The optical disk device 1 has a housing 2 and a tray 3 held in the housing 2 to freely appear. The housing 2 takes the shape of a bag in which metallic housing portions 2a and 2b are combined with each other and has such a structure that the tray 3 appears from the opening of the housing 2. An optical pick-up module 4 is attached to the tray 3 at a back face. A rail 3a is provided movably in both side portions of the tray 3, and is held in a rail holding portion 3b provided integrally with the tray 3. While the rail 3a is provided in only one of the side portions in FIG. 9, the same rail may be provided in the other side portion.
The housing portion 2a and the housing portion 2b are strongly fixed to each other by using engaging means and a spiral which are not shown. A conductive material such as a metal material, for example, iron, an iron alloy, aluminum, an aluminum alloy or a magnesium alloy is suitably used as the component of the housing 2. Moreover, it is also possible to use a component in which each housing portion is constituted by a resin material and a metal film having a high conductivity is formed thereon by using a method such as electrodeposition. Furthermore, the housing portions 2a and 2b may be constituted by a material of the same type respectively or materials of different types. Moreover, each of the main plane portions of the housing portions 2a and 2b has an average thickness of 0.3 mm to 1.6 mm. In the case in which the average thickness is comparatively small, the housing portion 2a and the housing portion 2b are constituted by metal materials, and a metal plate is formed by pressing, for example. In the case in which the average thickness is comparatively great, moreover, the housing portion 2a and the housing portion 2b are constituted by die casting (aluminum or a magnesium alloy).
The optical pick-up module 4 has at least a spindle motor 5 for rotating and driving an optical disk, a metallic cover 6 provided with an opening 6a from the spindle motor 5 to an outer periphery, and a carriage 7 having a part exposed from the opening 6a. The carriage 7 is held movably in a plurality of guide shafts provided on the optical pick-up module 4, and furthermore, can be moved to approach or separate from the spindle motor 5 by means of a feed motor which is not shown. 8 denotes a bezel provided on the front face of the tray 3. The bezel 8 is constituted to have such a size as to block the opening of the housing 2.
A light source such as a high power laser diode, various optical members and an objective lens for constituting an optical spot on an optical disk are mounted on the carriage 7. When recording is to be carried out over the optical disk, a high power light source and an IC for driving the light source are required. As a result, the light source or the IC generates heat very often so that a recording and reproducing characteristic is influenced. In the optical disk device 1 shown in FIG. 9, particularly, a reduction in a thickness and a size has been required. Therefore, there is a problem in that a thermal capacity is reduced. In the thin optical disk device 1 in which the central part of the housing 2 has a thickness of 14 mm or less, furthermore, 10 mm or less, particularly, this problem becomes remarkable.
A method of cooling the inside of the optical disk device has been described in (JP-A-11-25667 Publication) and (JP-A-2000-231782 Publication), for example.
These have described a method of leading an air flow generated during the rotation of an optical disk to the carriage 7 and cooling the same air flow. These methods have not supposed an optical disk device in which the central part of the housing 2 has a thickness of 14 mm or less or 10 mm or less. In such a very thin optical disk device, accordingly, a cooling effect is not always sufficient.